As a result of environmental considerations, increasing amounts of sulfur are being removed from natural gas and from flue gases, thus resulting in an abundant supply of this commodity. A decreasing world supply of crude oil increases the desirability of finding substitutes for crude oil-based products such as asphalt. Therefore, the use of a sulfur-based material that can be used as an extender for asphalt or as an asphalt replacement, for example, in highway construction is very desirable.
Sulfur has been proven to be a valuable component in construction materials. However, if unmodified, it imparts crystalline and brittle characteristics to those compositions in which it is used.
Accordingly, the prior art has modified sulfur with various materials. For example, sulfur has been modified with an olefin such as ethylene. Illustrative of this type of prior art are U.S. Pat. Nos. 2,039,070 and 2,135,747 to Duecker. Sulfur has also been modified with an olefinic hydrocarbon polymer derived from petroleum, as illustrated by U.S. Pat. No. 4,058,500 to Vroom. Other prior art has modified sulfur with styrene, styrene derivatives, or a cyclodiene such as dicyclopentadiene. Exemplary of this type of prior art is U.S. Pat. No. 3,459,717 to Signouret, U.S. Pat. No. 2,806,843 to Welsh, U.S. Pat. No. 3,823,019 to Dale et al., U.S. Pat. No. 3,887,504 to Woo, U.S. Pat. No. 3,997,355 to Santucci et al., U.S. Pat. No. 4,011,179 to Woo, U.S. Pat. No. 4,022,626 to McBee et al., U.S. Pat. No. 4,164,428 to Simic, the text at page 627 of Kirk-Othmer, Encyclopedia of Chemical Technology, 2nd Edition, Vol. 17, and B. R. Currell et al., Chapter 1 in New Uses of Sulfur (J. R. West, ed.), Advances in Chemistry Series 140, American Chemical Society, Washington, D.C., pp 1-17 (1975). The McBee et al. patent shows the use of dicyclopentadiene and styrene in combination as a modifying composition for sulfur.
Other prior art showing sulfur in combination with styrene or dicyclopentadiene is exemplified by U.S. Pat. No. 3,231,546 to Bertozzi et al. and by U.S. Pat. No. 3,264,239 to Rosen et al.
In addition, several formulations of a modified sulfur product called Sulphlex have been developed by the Southwest Research Institute to replace or extend asphalt in highway construction. Illustrative of these formulations in Sulphlex 126, which contains 61 wt.% sulfur and 13 wt.% of each of dicyclopentadiene, vinyltoluene and a light cut of coal tar; Sulphlex 230, which contains 70 wt.% sulfur and 15 wt.% of each of dicyclopentadiene and dipentene; and Sulphlex 233, which contains 70 wt.% sulfur, 12 wt.% dicyclopentadiene, 10 wt.% dipentene and 8 wt.% of vinyltoluene.
This prior art uses relatively expensive starting materials for the formation of the modified sulfur product. The need of the prior art to use relatively expensive starting materials such as styrene, dicyclopentadiene, dipentene, vinyltoluene or pre-reacted polysulfides has had, to the present time, an inhibiting effect on the general utilization of modified sulfur products of this type. Furthermore, this prior art does not provide a sulfur-based adduct and at the same time provide a residual by-product hydrocarbon mixture that is substantially free from dienes and pseudodienes. Dienes and pseudodienes are undesirable in refinery streams due to their tendency to form gums and to use large amounts of hydrogen in catalytic hydrotreatment processes. Moreover, this prior art fails to provide a road surface composition containing a modified sulfur product formed from a by-product hydrocarbon mixture available from petrochemical operations. In addition, this prior art does not provide coating compositions, foams, structural materials, sulfur cements and sulfur concretes formed from such a mixture.